I finished making edits to the last third of the securing-howto, from
section "vpn" (line #6161) to the end. I fixed as many FIXMEs as I
could, added and checked URLs, added <prgn> tags where needed, did
general editing, cleaned up whitespace, spell-checking, etc.

You can name the patch whatever you want, but then attach it to an email
and send it to the list; either Javi or someone else can then apply
it.

Then I created the patch using diff as suggested by Chris. However,
the patch is 208 Kb, and I didn't want to mail such a large attachment
to a public mailing list. Should I mail it to the maintainer
directly?

You have me beat by a long shot, Larry. I've been side tracked. Hope
to get to my piece this week! :-)